Temperature controlled nitrogen generation system

ABSTRACT

A nitrogen generation system includes a heat exchanger for receiving supply air and cooling air and providing temperature conditioned supply air, a flow control valve for controlling a flow of the cooling air through the heat exchanger, and an air separation module for receiving the temperature conditioned supply air and generating nitrogen-enriched air. The nitrogen generation system also includes a sensor for measuring a parameter of the nitrogen-enriched air selected from the group consisting of a temperature, a flow rate, an oxygen concentration, and combinations thereof, and a controller connected to the sensor and the flow control valve for controlling the flow of the cooling air through the heat exchanger based on the parameter of the nitrogen-enriched air measured by the sensor.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of U.S. application Ser. No. 16/175,293filed Oct. 30, 2018 for “TEMPERATURE CONTROLLED NITROGEN GENERATIONSYSTEM” by R. Ranjan and Z. A. Dardas, which in turn claims the benefitof U.S. application Ser. No. 14/736,819 filed Jun. 11, 2015 for“TEMPERATURE CONTROLLED NITROGEN GENERATION SYSTEM” by R. Ranjan and Z.A. Dardas,

BACKGROUND

This disclosure relates to aircraft safety, and more specifically to atemperature controlled nitrogen generation system.

Aircraft fuel tanks and containers can contain potentially combustiblecombinations of oxygen, fuel vapors, and ignition sources. In order toprevent combustion, the ullage of fuel tanks and containers is filledwith air with high nitrogen concentration, or nitrogen-enriched air(NEA), such that the oxygen concentration in the ullage is less than12%. A membrane-based nitrogen generation system (NGS) is commonly usedto produce NEA for inerting fuel tanks and containers. A membrane-basedNGS has an air separation module with a polymeric membrane whichseparates air into NEA and oxygen-enriched air (OEA). However, at agiven temperature, a polymeric membrane material has a fixedpermeability (defined as the transport flux of a gas through themembrane per unit driving force, i.e. partial pressure differencebetween the two sides of the membrane per unit membrane thickness) andselectivity (selectivity α_(AB) is defined as the ratio of permeabilityof one gas component A to the permeability of another gas component B ina gas mixture), which limits the performance of the air separationmodule. As a result, a larger and heavier NGS than desired is requiredto provide adequate fuel tank and container inerting throughout theflight profile of an aircraft.

SUMMARY

In one embodiment, a nitrogen generation system includes a heatexchanger for receiving supply air and cooling air and providingtemperature conditioned supply air, a flow control valve for controllinga flow of the cooling air through the heat exchanger, and an airseparation module for receiving the temperature conditioned supply airand generating nitrogen-enriched air. The nitrogen generation systemalso includes a sensor for measuring a parameter of thenitrogen-enriched air selected from the group consisting of atemperature, a flow rate, an oxygen concentration, and combinationsthereof, and a controller connected to the sensor and the flow controlvalve for controlling the flow of the cooling air through the heatexchanger based on the parameter of the nitrogen-enriched air measuredby the sensor.

In another embodiment, a nitrogen generation system includes a mixer forreceiving supply air and cooling air and providing temperatureconditioned supply air, a flow control valve for controlling a flow ofthe cooling air into the mixer, and an air separation module forreceiving the temperature conditioned supply air and generatingnitrogen-enriched air. The nitrogen generation system also includes asensor for measuring a parameter of the nitrogen-enriched air selectedfrom the group consisting of a temperature, a flow rate, an oxygenconcentration, and combinations thereof; and a controller connected tothe sensor and the flow control valve for controlling the flow of thecooling air through the heat exchanger based on the parameter of thenitrogen-enriched air measured by the sensor.

In another embodiment, a method of generating nitrogen-enriched airincludes cooling supply air with cooling air to produce temperatureconditioned supply air, flowing a flow of the temperature conditionedsupply air through an air separation module to generatenitrogen-enriched air, measuring a parameter of the nitrogen-enrichedair selected from the group consisting of a temperature, a flow rate, anoxygen concentration, and combinations thereof, and controlling a flowof the cooling air based on the parameter of the nitrogen-enriched air.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a temperature controlled nitrogengeneration system.

FIG. 2 is a schematic view of another embodiment of a temperaturecontrolled nitrogen generation system.

FIG. 3 is a schematic view of another embodiment of a temperaturecontrolled nitrogen generation system.

DETAILED DESCRIPTION

The present disclosure relates to a membrane-based nitrogen generationsystem (NGS) for generating air with high nitrogen concentration(nitrogen-enriched air). The NGS controls the temperature of themembrane in an air separation module (ASM) in order to control the flowrate and oxygen concentration of the nitrogen-enriched air (NEA)produced by the ASM. Controlling the temperature of the membrane allowsfor manipulation of the selectivity and permeability of the membrane ofthe ASM, which in turn controls the flow rate and oxygen concentrationof the NEA produced by the ASM. Controlling the temperature of themembrane of the ASM allows the NGS to meet varying demand for NEA duringan aircraft's flight profile. The NGS of the present disclosure improvesperformance of the ASM, and therefore allows for a reduction in volumeand weight of the ASM.

FIG. 1 is a schematic view of NGS 10. NGS 10 includes heat exchanger 12,supply air input 14, flow control valve 16, cooling air input 18,cooling air line 20, cooling air output 22, temperature conditioned airline 24, ASM 26, NEA line 28, oxygen-enriched air (OEA) line 30,controller 32, sensor 34, and sensor 36.

Heat exchanger 12 receives supply air through supply air input 14. Flowcontrol valve 16 receives cooling air through cooling air input 18.Cooling air flows out of flow control valve 16 and into heat exchanger12 through cooling air line 20. Used cooling air exits heat exchanger 12through cooling air output 22. Temperature conditioned air exits heatexchanger 12 through temperature conditioned air line 24. ASM 26receives temperature conditioned air through temperature conditioned airline 24. ASM 26 produces NEA and OEA. NEA exits ASM 26 through NEA line28, and OEA exits ASM 26 through OEA line 30. Controller 32 is connectedto flow control valve 16, sensor 34, and sensor 36. Sensor 34 measuresparameters of the temperature conditioned air in temperature conditionedair line 24. Sensor 36 measures parameters of NEA in NEA line 28.

NGS 10 generates NEA for an aircraft for inerting fuel tanks and othercontainers. In order to generate NEA, supply air, such as bleed air,flows through supply air input 14 and into heat exchanger 12. The supplyair entering heat exchanger 12 is between about 300 degrees Fahrenheit(148 degrees Celsius) and about 450 degrees Fahrenheit (233 degreesCelsius). Cooling air, such as ram air, also flows into heat exchanger12 through cooling air line 20. The cooling air flows into flow controlvalve 16 through cooling air input 18. Flow control valve 16 controlsthe flow of cooling air through cooling air line 20 and into heatexchanger 12. The cooling air entering heat exchanger 12 is betweenabout −50 degrees Fahrenheit (−46 degrees Celsius) and about 110 degreesFahrenheit (43.4 degrees Celsius).

Heat exchanger 12 is an air-to-air heat exchanger, such as a plate heatexchanger or a shell and tube heat exchanger. The cooling air flowsthrough heat exchanger 12 to cool the supply air flowing through heatexchanger 12. Temperature conditioned air exits heat exchanger 12through temperature conditioned air line 24, and used cooling air exitsheat exchanger 12 through cooling air output 22. Flow control valve 16controls the flow of cooling air into heat exchanger 12 in order tocontrol the temperature of the temperature conditioned air exiting heatexchanger 12 and entering ASM 26. The temperature conditioned airexiting heat exchanger 12 is between about 60 degrees Fahrenheit (15degrees Celsius) and about 200 degrees Fahrenheit (93.4 degreesCelsius).

The temperature conditioned air flows through temperature conditionedair line 24 and into ASM 26. Sensor 34 measures parameters such astemperature, flow rate, and oxygen concentration of the temperatureconditioned air in temperature conditioned air line 24. ASM 26 can be amembrane-based ASM made of a polymer such aspoly(1-trimethylsilyl-1-propyne), Teflon, silicone rubber,poly(4-methyl-1-pentene), poly(phenylene oxide), ethyl cellulose,polyimide, polysulfone, polyaramide, tetrabromo bis polycarbonate, orcombinations thereof. ASM 26 separates the temperature conditioned airto generate NEA and OEA. NEA exits ASM 26 through NEA line 28 and isdistributed to fuel tanks and other containers in the aircraft thatrequire inerting. Sensor 36 measures parameters such as temperature,flow rate, and oxygen concentration of the NEA in NEA line 28. Theconcentration of oxygen in the NEA exiting ASM 26 is between about 1%and about 12%. OEA exits ASM 26 through OEA line 30 and is dumpedoverboard.

NGS 10 controls the flow rate and oxygen concentration of the NEA in NEAline 28 with controller 32. Controller 32 is connected to flow controlvalve 16, sensor 34, and sensor 36. Controller 32 controls the flow ofthe cooling air into heat exchanger 12 based on the value of theparameters measured by sensor 36. Sensor 36 provides measurements ofparameters such as temperature, flow rate, and oxygen concentration ofthe NEA in NEA line 28 to controller 32. The temperature of the NEA inNEA line 28 is the temperature of the membrane in ASM 26. Based on thedesired oxygen concentration and flow rate of the NEA in NEA line 28,controller 32 controls how much flow control valve 16 is opened orclosed in order to control the temperature of the temperatureconditioned air entering ASM 26 and thus control the temperature of themembrane of ASM 26. NGS 10 can also include sensor 34 in order tomeasure parameters such as temperature, flow rate, and oxygenconcentration of the temperature conditioned air entering ASM 26, butsensor 36 provides the primary control signal based upon whichcontroller 32 adjusts the flow of the cooling air into heat exchanger12.

NGS 10 generates NEA with varying flow rate and oxygen concentrationbased on demand during an aircraft's flight profile. The flow rate andoxygen concentration of the NEA leaving ASM 26 is controlled bycontrolling the temperature of the membrane of ASM 26. The temperatureof the membrane of ASM 26 is controlled by controlling the temperatureof the temperature conditioned air entering ASM 26. The temperatureconditioned air entering ASM 26 can be between about 60 degreesFahrenheit (15 degrees Celsius) and about 200 degrees Fahrenheit (93.4degrees Celsius). At lower temperatures, ASM 26 generates NEA with alower oxygen concentration (can be as low as about 1%) and a lower flowrate. At higher temperatures, ASM 26 generates NEA with a higher oxygenconcentration (can be as high as about 12%) and a higher flow rate. Thespecific temperature ranges depend on the material of the membrane.

During the ascent and cruise portions of the flight profile of anaircraft, a lower amount of NEA is required. During the ascent andcruise portions, NGS 10 thus controls the temperature of the membrane ofASM 26 to produce NEA with a lower flow rate and lower oxygenconcentration (under 7-8% oxygen and as low as about 1% oxygen). Themost NEA is required during the descent portion of the flight profile.During the descent portion, NGS 10 thus controls the temperature of themembrane of ASM 26 to produce NEA with a higher flow rate and higheroxygen concentration (between about 10% and about 12%). NGS 10 isadvantageous, because NGS 10 improves performance of ASM 26 bycontrolling the temperature of the membrane of ASM 26, allowing for areduction in volume and weight of ASM 26.

FIG. 2 is a schematic view of nitrogen generation system 100. NGS 100includes heat exchanger 112, supply air input 114, flow control valve116, cooling air input 118, cooling air line 120, flow control valve121, cooling air output 122, temperature conditioned air line 123,temperature conditioned air line 124, temperature conditioned air line125, ASM 126, jacket 127, NEA line 128, OEA line 130, controller 132,sensor 134, and sensor 136.

Heat exchanger 112 receives supply air through supply air input 114.Flow control valve 116 receives cooling air through cooling air input118. Cooling air flows out of flow control valve 116 and into heatexchanger 112 through cooling air line 120. Used cooling air exits heatexchanger 112 through cooling air output 122. Temperature conditionedair exits heat exchanger 112 through temperature conditioned air line124. Flow control valve 121 receives temperature conditioned air throughtemperature conditioned air line 124. Temperature conditioned air flowsout of flow control valve 121 and into ASM 126 through temperatureconditioned air line 123. ASM 126 produces NEA and OEA. Jacket 127surrounds ASM 126 and receives temperature conditioned air throughtemperature conditioned air line 125. NEA exits ASM 126 through NEA line128, and OEA exits ASM 126 through OEA line 130. Controller 132 isconnected to flow control valve 116, flow control valve 121, sensor 134,and sensor 136. Sensor 134 measures parameters of the temperatureconditioned air in temperature conditioned air line 123. Sensor 136measures parameters of NEA in NEA line 128.

NGS 100 functions similarly to NGS 10 in FIG. 1, except NGS 100 alsoincludes jacket 127. Supply air, such as bleed air, flows through supplyair input 114 and into heat exchanger 112. Cooling air, such as ram air,also flows into heat exchanger 112 through cooling air line 120. Thecooling air flows into flow control valve 116 through cooling air input118. Flow control valve 116 controls the flow of cooling air throughcooling air line 120 and into heat exchanger 12.

The cooling air flows through heat exchanger 112 to cool the supply airflowing through heat exchanger 112. Temperature conditioned air exitsheat exchanger 112 through temperature conditioned air line 124, andused cooling air exits heat exchanger 112 through cooling air output122. Flow control valve 116 controls the flow of cooling air into heatexchanger 112 in order to control the temperature of the temperatureconditioned air exiting heat exchanger 112 and entering ASM 126 andjacket 127.

The temperature conditioned air flows through temperature conditionedair line 124 and into flow control valve 121. Flow control valve 121 canbe a three way valve. Flow control valve 121 controls the flow oftemperature conditioned air into ASM 126 through temperature conditionedair line 123 and the flow of temperature conditioned air into jacket 127through temperature conditioned air line 125.

Sensor 134 measures parameters such as temperature, flow rate, andoxygen concentration of the temperature conditioned air in temperatureconditioned air line 123. ASM 126 separates the temperature conditionedair to generate NEA and OEA. NEA exits ASM 126 through NEA line 128 andis distributed to fuel tanks and other containers in the aircraft thatrequire inerting. Sensor 136 measures parameters such as temperature,flow rate, and oxygen concentration of the NEA in NEA line 128.

NGS 100 controls the flow rate and oxygen concentration of the NEA inNEA line 128 with controller 132. Controller 132 is connected to flowcontrol valve 116, flow control valve 121, sensor 134, and sensor 136.Controller 132 controls the flow of the cooling air into heat exchanger112 and the flow of temperature conditioned air into ASM 126 and jacket127 based on the value of the parameters measured by sensor 136. Sensor136 provides measurements of parameters such as temperature, flow rate,and oxygen concentration of the NEA in NEA line 128 to controller 132.The temperature of the NEA in NEA line 128 is the temperature of themembrane in ASM 126.

Based on the desired oxygen concentration and flow rate of the NEA inNEA line 128, controller 132 controls how much flow control valve 116and flow control valve 121 are opened or closed in order to control thetemperature of the temperature conditioned air entering ASM 126 and thuscontrol the temperature of the membrane of ASM 126. Controller 132 alsocontrols how much flow control valve 121 is opened or closed in order toprovide further temperature control of the membrane of ASM 126 byflowing additional temperature conditioned air through jacket 127.Flowing temperature conditioned air through both ASM 126 and jacket 127is advantageous, because the temperature of the membrane of ASM 126 canbe changed at a quicker rate. NGS 100 can also include sensor 134 inorder to measure parameters such as temperature, flow rate, and oxygenconcentration of the temperature conditioned air entering ASM 126, butsensor 136 provides the primary control signal based upon whichcontroller 132 adjusts the flow of the cooling air into heat exchanger112 and temperature conditioned air into ASM 126 and jacket 127.

FIG. 3 is a schematic view of nitrogen generation system 200. NGS 200includes mixer 212, supply air input 214, flow control valve 216,cooling air input 218, cooling air line 220, temperature conditioned airline 224, ASM 226, NEA line 228, OEA line 230, controller 232, sensor234, and sensor 236.

Mixer 212 receives supply air through supply air input 214. Flow controlvalve 216 receives cooling air through cooling air input 218. Coolingair flows out of flow control valve 216 and into mixer 212 throughcooling air line 220. Temperature conditioned air exits mixer 212through temperature conditioned air line 224. ASM 226 receivestemperature conditioned air through temperature conditioned air line224. ASM 226 produces NEA and OEA. NEA exits ASM 226 through NEA line228, and OEA exits ASM 226 through OEA line 230. Controller 232 isconnected to flow control valve 216, sensor 234, and sensor 236. Sensor234 measures parameters of the temperature conditioned air intemperature conditioned air line 224. Sensor 236 measures parameters ofNEA in NEA line 228.

NGS 200 functions similarly to NGS 10 in FIG. 1, except NGS 200 includesmixer 212 instead of heat exchanger 12. Supply air, such as bleed air,flows through supply air input 214 and into mixer 212. The supply airentering mixer 212 is between about 30 psi and about 40 psi. Cooling airalso flows into mixer 212 through cooling air line 220. The cooling airflows into flow control valve 216 through cooling air input 218. Flowcontrol valve 216 controls the flow of cooling air through cooling airline 220 and into mixer 212. The cooling air entering mixer 212 isbetween about 30 psi and about 40 psi.

Mixer 212 mixes the supply air and cooling air in order to producetemperature conditioned air. Temperature conditioned air exits mixer 212through temperature conditioned air line 224. Flow control valve 216controls the flow of cooling air into mixer 212 in order to control thetemperature of the temperature conditioned air exiting mixer 212 andentering ASM 226. The temperature conditioned air flows throughtemperature conditioned air line 224 and into ASM 226. Sensor 234measures parameters such as temperature, flow rate, and oxygenconcentration of the temperature conditioned air in temperatureconditioned air line 224. ASM 226 separates the temperature conditionedair to generate NEA and OEA. NEA exits ASM 226 through NEA line 228 andis distributed to fuel tanks and other containers in the aircraft thatrequire inerting. Sensor 236 measures parameters such as temperature,flow rate, and oxygen concentration of the NEA in NEA line 228. OEAexits ASM 226 through OEA line 230 and is dumped overboard.

NGS 210 controls the flow rate and oxygen concentration of the NEA inNEA line 228 with controller 232. Controller 232 is connected to flowcontrol valve 216, sensor 234, and sensor 236. Controller 232 controlsthe flow of the cooling air into mixer 212 based on the value of theparameters measured by sensor 236 in the same manner that controller 32in FIG. 1 controls the flow of cooling air into heat exchanger 12.

Discussion of Possible Embodiments

The following are non-exclusive descriptions of possible embodiments ofthe present invention.

A nitrogen generation system according to an exemplary embodiment ofthis disclosure, among other possible things includes a heat exchangerfor receiving supply air and cooling air and providing temperatureconditioned supply air, a first flow control valve for controlling aflow of the cooling air through the heat exchanger, and an airseparation module for receiving the temperature conditioned supply airand generating nitrogen-enriched air. The nitrogen generation systemalso includes a first sensor for measuring a parameter of thenitrogen-enriched air selected from the group consisting of atemperature, a flow rate, an oxygen concentration, and combinationsthereof, and a controller connected to the first sensor and the firstflow control valve for controlling the flow of the cooling air throughthe heat exchanger based on the parameter of the nitrogen-enriched airmeasured by the first sensor.

The nitrogen generation system of the preceding paragraph can optionallyinclude, additionally and/or alternatively, any one or more of thefollowing features, configurations and/or additional components:

A further embodiment of the foregoing nitrogen generation system, andfurther including a second sensor for measuring a parameter of thetemperature conditioned supply air selected from the group consisting ofa temperature, a flow rate, an oxygen concentration, and combinationsthereof, wherein the second sensor is connected to the controller.

A further embodiment of any of the foregoing nitrogen generationsystems, wherein the heat exchanger is a plate heat exchanger or a shelland tube heat exchanger.

A further embodiment of any of the foregoing nitrogen generationsystems, wherein the supply air is bleed air and the cooling air is ramair.

A further embodiment of any of the foregoing nitrogen generationsystems, wherein the air separation module comprises a membrane.

A further embodiment of any of the foregoing nitrogen generationsystems, wherein the membrane is made of a polymer selected from thegroup consisting of poly(1-trimethylsilyl-1-propyne), Teflon, siliconerubber, poly(4-methyl-1-pentene), poly(phenylene oxide), ethylcellulose, polyimide, polysulfone, polyaramide, tetrabromo bispolycarbonate, and combinations thereof.

A further embodiment of any of the foregoing nitrogen generationsystems, and further including a jacket surrounding the air separationmodule and a second flow control valve connected to the controller.

A further embodiment of any of the foregoing nitrogen generationsystems, wherein the second flow control valve is a three way valve forcontrolling a first flow of the temperature conditioned supply air intothe air separation module and controlling a second flow of thetemperature conditioned supply air into the jacket.

A nitrogen generation system according to an exemplary embodiment ofthis disclosure, among other possible things includes a mixer forreceiving supply air and cooling air and providing temperatureconditioned supply air, a flow control valve for controlling a flow ofthe cooling air into the mixer, and an air separation module forreceiving the temperature conditioned supply air and generatingnitrogen-enriched air. The nitrogen generation system also includes afirst sensor for measuring a parameter of the nitrogen-enriched airselected from the group consisting of a temperature, a flow rate, anoxygen concentration, and combinations thereof, and a controllerconnected to the first sensor and the flow control valve for controllingthe flow of the cooling air through the heat exchanger based on theparameter of the nitrogen-enriched air measured by the first sensor.

The nitrogen generation system of the preceding paragraph can optionallyinclude, additionally and/or alternatively, any one or more of thefollowing features, configurations and/or additional components:

A further embodiment of the foregoing nitrogen generation system, andfurther including a second sensor for measuring a parameter of thetemperature conditioned supply air selected from the group consisting ofa temperature, a flow rate, an oxygen concentration, and combinationsthereof, wherein the second sensor is connected to the controller.

A method of generating nitrogen-enriched air according to an exemplaryembodiment of this disclosure, among other possible things includescooling supply air with cooling air to produce temperature conditionedsupply air, flowing a first flow of the temperature conditioned supplyair through an air separation module to generate nitrogen-enriched air,measuring a parameter of the nitrogen-enriched air selected from thegroup consisting of a temperature, a flow rate, an oxygen concentration,and combinations thereof, and controlling a flow of the cooling airbased on the parameter of the nitrogen-enriched air.

The method of the preceding paragraph can optionally include,additionally and/or alternatively, any one or more of the followingfeatures, configurations and/or additional components:

A further embodiment of the foregoing method, wherein cooling the supplyair includes flowing the supply air through a heat exchanger and flowingthe flow of the cooling air through the heat exchanger.

A further embodiment of any of the foregoing methods, and furtherincluding flowing a second flow of temperature conditioned supply airthrough a jacket surrounding the air separation module.

A further embodiment of any of the foregoing methods, and furtherincluding controlling the first flow of the temperature conditionedsupply air through the air separation module and controlling the secondflow of the temperature conditioned supply air through the jacket basedon the measured parameter of the nitrogen-enriched air.

A further embodiment of any of the foregoing methods, wherein coolingthe supply air includes mixing the flow of the cooling air and thesupply air.

A further embodiment of any of the foregoing methods, wherein thetemperature of the supply air is between 148 degrees Celsius and 233degrees Celsius.

A further embodiment of any of the foregoing methods, wherein thetemperature of the cooling air is between −46 degrees Celsius and 43.4degrees Celsius.

A further embodiment of any of the foregoing methods, wherein thetemperature of the nitrogen-enriched air is between 15 degrees Celsiusand 93.4 degrees Celsius.

A further embodiment of any of the foregoing methods, and furtherincluding measuring a parameter of the temperature conditioned supplyair selected from the group consisting of a temperature, a flow rate, anoxygen concentration, and combinations thereof, wherein the secondsensor is connected to the controller.

A further embodiment of any of the foregoing methods, wherein the oxygenconcentration of the nitrogen-enriched air is less than 12 percent.

While the invention has been described with reference to an exemplaryembodiment(s), it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

The invention claimed is:
 1. A method of generating nitrogen-enrichedair, the method comprising: cooling supply air with cooling air toproduce temperature conditioned supply air; flowing a first flow of thetemperature conditioned supply air through an air separation module togenerate nitrogen-enriched air; flowing a second flow of temperatureconditioned supply air through a jacket surrounding the air separationmodule; measuring a parameter of the nitrogen-enriched air selected fromthe group consisting of a temperature, a flow rate, an oxygenconcentration, and combinations thereof; controlling a flow of thecooling air based on the parameter of the nitrogen-enriched air.
 2. Themethod of claim 1, wherein cooling the supply air comprises: flowing thesupply air through a heat exchanger; and flowing the flow of the coolingair through the heat exchanger.
 3. The method of claim 1, and furthercomprising controlling the first flow of the temperature conditionedsupply air through the air separation module and controlling the secondflow of the temperature conditioned supply air through the jacket basedon the measured parameter of the nitrogen-enriched air.
 4. The method ofclaim 1, wherein the temperature of the supply air is between 148degrees Celsius and 233 degrees Celsius.
 5. The method of claim 1,wherein the temperature of the cooling air is between −46 degreesCelsius and 43.4 degrees Celsius.
 6. The method of claim 1, wherein thetemperature of the nitrogen-enriched air is between 15 degrees Celsiusand 93.4 degrees Celsius.
 7. The method of claim 1, and furthercomprising measuring a parameter of the temperature conditioned supplyair selected from the group consisting of a temperature, a flow rate, anoxygen concentration, and combinations thereof, wherein the secondsensor is connected to the controller.
 8. The method of claim 1, whereinthe oxygen concentration of the nitrogen-enriched air is less than 12percent.
 9. A method of generating nitrogen-enriched air, the methodcomprising: cooling supply air with cooling air to produce temperatureconditioned supply air by: flowing the supply air through a heatexchanger; and flowing the flow of the cooling air through the heatexchanger; flowing a first flow of the temperature conditioned supplyair through an air separation module to generate nitrogen-enriched air;flowing a second flow of temperature conditioned supply air through ajacket surrounding the air separation module; measuring a parameter ofthe nitrogen-enriched air selected from the group consisting of atemperature, a flow rate, an oxygen concentration, and combinationsthereof; controlling a flow of the cooling air based on the parameter ofthe nitrogen-enriched air.
 10. The method of claim 9, wherein the supplyair is bleed air and the cooling air is ram air.
 11. The method of claim9, wherein the air separation module comprises a membrane made of apolymer selected from the group consisting ofpoly(1-trimethylsilyl-1-propyne), Teflon, silicone rubber,poly(4-methyl-1-pentene), poly(phenylene oxide), ethyl cellulose,polyimide, polysulfone, polyaramide, tetrabromo bis polycarbonate, andcombinations thereof.
 12. The method of claim 9, wherein the jacket isconfigured to receive a portion of the temperature conditioned supplyair simultaneously with the air separation module receiving temperatureconditioned supply air.